[codex] Fix face bounding box return type

[thehanslevi]

Summary

• correct the face_bboxes return type from BBOX, to BBOX
• keep both bounding-box outputs on the same ComfyUI custom type

The comma was part of the type string rather than Python tuple syntax, so the fifth output advertised a different type from the adjacent bboxes output.

Closes #34.

Validation

• python3 -m compileall -q .
• AST assertion that RETURN_TYPES and RETURN_NAMES both contain five entries and the final two types are BBOX
• git diff --check

The repository does not include a test suite, so no end-to-end ComfyUI workflow test was available.